Mancini told friends in Italy he thought the Premier League race was over in April when United opened up an eight-point lead.
But Kidd used all the experience he garnered as Sir Alex Ferguson’s assistant at Old Trafford to revive the Italian and his players.
A source close to Mancini told the Sunday Mirror: “People thought that Roberto was playing mind games when he said United would win the title.
“He is amused by this because he wasn’t being clever. He genuinely thought it was impossible for there to be any other outcome than United being champions.
“Roberto was impressed with the role that Brian Kidd played in making sure the players and the coaching staff didn’t give up.
“He told Roberto that United would drop points. He told the players and the other coaches that they would have even bigger regrets if United dropped points and City were not there to take advantage.
“At a dinner in Italy, Roberto admitted that Kidd played a big part in the title win. His respect for him has grown even more because of it.”